Method of mounting pivoted latches on self-acting needles for knitting and relooping machines



June 21, 1955 M vlToUx METHOD 0F MOUNTING PIVOTED LATCHES 0N SELF-ACTINGNEEDLES FOR KNITTING .AND REL-DOPING MACHINES Filed Sept. 21, 1950 Ill".

ATTO lNE'zLS Unite States Patent METHOD F MOUNTING PIV OTED LATCHES ONSELF-ACTING NEEDLES FR KNITTING AND RELOOPING MACHINES Marcel Vitoux,Troyes, France Application September 21, 1950, Serial No. 185,914

1 Caim. (Cl. 163-5) This invention relates to needles of the kind usedfor performing knitting and relooping works either by hand or by meansof machines, in which the catch or beak is closed by a rocking latchmounted for pivotal motion in a suitable slit or groove formed in thebody or stem of the needle.

It is known that in needles of this type, the latch is mounted, as arule, for pivotal motion, on a tiny metal pin having its ends retainedthrough screw means or riveted in upturned side portions of the needlebody ou either sides of the latch.

It is generally admitted thatthis method of mounting latches for pivotalmotion in latch-needles offers serious drawbacks. Thus, the assemblingof such tiny parts is most difficult as the tapping, thread-cutting andriveting steps are delicate operations whereby detrimental in- ZJaccuracies and a high percentageof rejections are frequentlyexperienced; furthermore, when the pin ends have been riveted in theaforesaid side portions of the needle body and the thus formed assemblyhardened, it

is impossible to remove the latch for replacement, a

still further trouble resulting from this conventional mounting beingthe' fact that the thread is sometime caught by the riveted ends of thepivot pin.

Moreover, metallic pins. are a drawback in themselves as they wear outquite rapidly if badly lubricated, while correct lubrication of thesemembers'is frequently made impossible when knitting white, or clearcoloured fabrics, this wear being always considerable owing to themetalto-metal friction produced.

The object of this invention is to avoid these various drawbacks and itis based on the principle of utilizing the properties of certainsynthetic plastic materials which can be deformed temporarily whencompression or pulling forces are applied thereto, with or without theassistance of heat, and resume their initial normal shapes and volumeswhen the application of compression and pulling forces is released,while these initial normal shapes land volumes can be retainedindefinitely, through the action of heat if thermosetting plasticmaterials are used.

More particularly, one object of this invention is to provide a novelmethod of mounting rocking latch or clasp members for pivotal motion onself-acting needles of the type used for knitting and relooping works,this method being characterized by the fact that the pin bores of thelatch member and side portions of the needle body are given smallerdiameter and larger diameters respectively, than the normal outerdiameter of the latch pivot pin, or conversely, larger diameter andsmaller diameters respectively, than this said normal outer diameter,and that, in combination, this pivot pin for pivotally mounting thelatch member between the side portions of the needle body consists of acylindrical stub of synthetic plastic material adapted to be deformedmomentarily, during the assembling of the parts, underthe influence ofvarious compression, pulling and/or torsional forces, before resumingits initial normal shape and volume.

Preferably, the synthetic plastic material used for ZLZB Patented June21, 1955 forming this cylindrical stub to be used as a latch pin inself-acting needles for knitting and relooping machines will be selectedin the superpolyamid group and consists, more preferably, of a syntheticresin known and sold under the trade name of Nylon In order better tounderstand the methodaccording to the invention and how same may becarried out practically, the accompanying drawing illustratesYdiagrammatically some'embodiments of the invention given solely by wayof example. In the drawing: ,Y

Fig. l is` an elevational side view of a latch-needle for knittingmachines, of known type, illustrating the kind of needles to which thepresent invention is applicable, and wherein 1 is the body or stem ofthe needle terminating in a hook portion 2, and 3 the rocking latchmounted for pivotal motion about its metal pin 4.

Fig. 2 is a cross-sectional view along the pivot axis, according to aiirst embodiment of the invention;

Fig. 3 is a similar view of a second embodiment, and

Fig. 4 is another similar view ofl a modified embodiment.

Referring to Figs. 2, 3 and 4 of the drawing, which illustrate, at amuch enlarged scale considering the slenderness of latch-needles, thethree different embodiments of the invention, 1a, 1a are the two sideportions which dene the slit or groove 5 formed in the needle body 1 andbetween which the latch proper 3 is mounted for pivotal motion about itspin 4, consisting, according to the invention, of a cylindrical stub ofNylon thread,

the initial normal 'diameter of which is designated by the reference.letter a.

6`is the pin bore formed in the latch and 7, 7 those formed through theside portions 1a, 1a to receive the t ends of the pivot pin 4.

Now regarding the iirst embodiment illustrated in Fig.

stub 4, while the diameter of bores 7, 7 in side portionsA 1a, 1a of theneedle body issomewhat larger than the initial normal diameter a of thisstub.

,Thus, the method of assembling consists in placing the latch 3 in slit5 with the pin bore 6 in alignment with the bores 7, 7 of side portionsla, 1a; and,'after having sharpened orpointed the end of a Nylon threadhaving an initial normal diameter a slightly greater than the pin bore6, in threading this Nylon thread, first, freely through one of thebores 7, 7 of the side portions of the needle b ody 1; and then, ingradually pushing and twisting said thread through the pin bore 6 of thelatch, until the pointed end of said thread comes out freely from thebore 7 of the other side portion of the needle.

With such a forced threading, the thread will be deformed and elongatedwhile progresing through the parts and then, said thread is cut .tolength, i. e. ush with the outer faces of the needle side portions bymeans of a sharp blade or other suitable device.

As the Nylon thread has a tendency to resume its initial normal volume,the stub portion thereof which is placed in the latch pin bore 6 will betightly clamped while the end portions of the pin will resume freelytheir initial normal diameter a while, at the same time, retractingthemselves inside bores 7, 7 of side portion 1a, la in which they arejournaled, thus avoiding any risk of catching the threads being knitted.

if desired and for additional safety, a further step may be carried outto prevent the pin ends from projecting from the needle side faces bylightly driving-in these ends with the assistance of a punch heated at asuitable temperature.

Referring now to the second embodiment illustrated in Fig. 3, it will benoted that in view of pivotally 3 mounting the latch, the diameter ofits pin bore 6 is made somewhat larger than the initial normal diametera of stub 4, While the diameter of bores 7, 7 in side portions 1a, la,is made slightly smaller than the initial normal diameter of said stub.

Thus, this method of assembling, which is much similar to the firstembodiment described in connection with Fig. 2, consists in threadingfreely the pointed end of the nylon thread into the bore 7 of one of theneedle side portions, then, force the thread by pushing and twisting itthrough this bore 7 and in so continuing moving the thread gradually andsuccessively through said bore, until the pointed end which has freelypassed through the latch bore 6, will emerge from the other side face ofthe needle through the corresponding bore 7 from which it will then bepulled in combination with the pushing action still exerted on thethread on the other or first side.

With this forced threading performed through cornzined extrusion anddrawing of the thread, this latter will be deformed and elongated, thelast step consisting, as in the iirst embodiment, in cutting the threadflush with both side faces of the latch-needle to form the pin or stub.

As it tends to resume its initial volume, the stub portion locatedinside the latch bore 6 comprised between the side portions la, la ofthe needle will expand to its initial normal diameter a, While the pinends are tightly held in bores 7, 7 with their outer faces retractedinside these bores, whereby any catching of the knitted threads duringoperation of the needle is substantially prevented.

Referring now to the modified embodiment illustrated in Fig. 4, it willbe seen that in view of the pivotal mounting of latch 3 in the needle,the diameter of the latch bore 6 is also slightly larger than theinitial normal diameter a of stub 4, while the diameter of bores,

. 7, 7 in side portions la, 1a are substantially the same as the initialnormal diameter a of stub 4, said bores being countersunk at 7a,V 7a.

Under these conditions, the assembling is simplified as it simplyconsists in engaging successively the Nylon thread through bores 7, 6,7, almost without forcing it, then cutting said thread flush with theouter faces of the needle, and finally driving the ends of the thusformed pin into the bores by means of a heated punch so as to form theseends with countersunk heads 4a, whereby pin 4 will be safely heldagainst axial motion and prevented from catching the threads when theneedle is in operation. t

l This method of mounting the latch for pivotal m`o tion inlatch-needles avoids the 'drawbacks resulting from conventional metalpin assemblies and is also arl-- vantageous in that worn or otherwisespoiled latches may be readily replaced by driving out the pins from theassembly, by simply using a chasing point.

While I have shown and described some embodiments in which my inventionmay be carried out, it will kbe understood that various details may bealtered Without departing from the spirit and scope thereof.Furthermore, i do not wish to be construed as limiting my invention tothe specific embodiments illustrated, exceptk as it may be limited inthe appended claim.

I claim:

A method of mounting a latch or clasp member for i pivotal motion on aself-acting needle for knitting and relooping, said method comprisingforming a pin-bore in a latch member, forming a latch-receiving groovein a needle body, whereby said portions are formed in the needle bodyonk opposite sides of said groove, forming a pair of alined pin-bores insaid side portions, said latch pin-boreshaving a diameter which isdifferent fromthe diameter of said pair of side pin-bores, placing saidlatch member in said groove with the latch pin-bore in axial alinementwith said pair of side pin-bores, forcing a pin of synthetic plasticmaterial of the superpolyamide groupthe initial normal diameterof whichis smaller than the largest diameter ofsaidy bores and larger than thesmallest diameter of said bores, through said Vbores, while subjectingsaid pin to axial compression and deforming it momentarily until the pinis positioned beyond said bores, cutting said pin flush with both outerfaces of said side portions, and allowing a portion of the pin to resumeits initial normal diameter While the end portionsv of the pin areretracted into said side pin-bores, whereby said latch member will bejournalled for kfree pivot motion. l i Y References Cited in the file ofthis patent

